The Mississippi River – Has it Changed?

Recently we have received a few inquiries about the Mississippi and the articles we have written about Zarahemla not being in Iowa as some theorists claim. One of the reason for this stand about the Mississippi is that it does not meet the criteria of the River Sidon in the scriptural record, nor does the topography around the area, including Iowa and Illinois, especially in that part where Nauvoo and across the river in Iowa, from Montrose and Zarahemla to Keokuk. 
    As one reader responded to our article: “The river was not wide two thousand years ago. There were rapids in the Mississippi river just north of Keokuk, Iowa, that current dams cover. The land is Not flat as a pancake. I have to travel up a hill to return to my home. Obviously you know not what you speak about.” Another wrote: “Nobody knows how the Mississippi river looked like 2000 years ago.”
    So we thought we would take these and for the others received, write a full article on the issue, since there is sufficient information to show these readers the condition of the Mississippi and what is known about it today from modern technology as it appeared in the past. First of all, the Mississippi River has always been a very shallow river, with shifting sandbars, snags, shoals, and rocks (rapids) that have always been a threat to navigation along the river. The first major boats (besides canoes, poleboats and flatboats or keelboats) to navigate the Mississippi were steam-driven side or stern paddlewheelers. These were flat-bottomed vessels necessary on the Mississippi because of the shallowness of the river.

Because of the shallow, uneven bottom of the Mississippi, locks were built to raise vessels over the shallows, rapids, and sand bars. Top: The uneven rise of the Mississippi River; Bottom: the use of locks to raise a ship from one level to another over the uneven bottom. No ship of any size, like Nephi's deep ocean vessel, could have maneuvered up the Mississippi anciently before these locks were built

In fact, the Mississippi River has always been a navigatable nightmare for early vessels, and until the Corps of Engineers began dredging out the bottom for smoother sailing routes, and building locks to allow flat-bottom paddlewheelers to sail above rapids and uneven bottomed shoals, navigation beyond Baton Rouge Louisiana was next to impossible for any deep ocean or blue water vessel, such as Nephi's ship.

Top: Lock #19 along the Mississippi River at Keokuk, Iowa, across from Illinois: Bottom: 1878 book “Map of a Reconnaissance of the Mississippi River from Cairo, Ill. To New Orleans La.” Including detailed drawings of Des Moines Rapids, locks and canal, From the U.S. Army Corps of Engineers

Secondly, we have written about the Des Moines Rapids on numerous occasions on this subject, which are those between Nauvoo and Keokuk, Iowa. This 12-mile stretch of rapids was the northern head of navigation on the Mississippi River for many years. Cargo headed up river or down river had to be unloaded from the boats and carried past the rapids in horse-drawn wagons until the U.S. Corps of Engineers began clearing the Mississippi River as early as 1829. From 1831 to 1833, Lieutenant Robert E. Lee ran a project to remove snags and blast the largest rocks in the rapids, though it did not solve the problem, it made it less difficult. A canal was needed, but had to wait until after the Civil War was concluded.
    The Canal envisioned by Lee was approved with construction started in 1866, as the canal was built along the west bank of the river. Starting at Keokuk (just south of Zarahemla, Iowa), a wall was built 8 miles long to create a river channel that was independent of the main Mississippi River channel. This channel was deepened, and three locks were installed, opening to river traffic in 1877. A further 4 miles of canal was built south of Keokuk down to the Des Moines River. This was accomplished by blasting the bedrock to create a deeper channel along the west side of the river. This part of the canal was not separated from the main river as the upper portion was, and featured an overall depth of not less than 5 feet for the flat bottomed paddlers to clear.
    Later, in the 1930s, the Upper Mississippi was completed, when the U.S. Army Corp of Engineer’s dug a 9-foot-channel project that resulted in today’s 29 locks and dams on the Upper Mississippi River. The S.S. Thorpe’s maiden voyage marked the development of towboat and barge transportation on the Upper Mississippi, and today’s towboats, powered by two 3,000 HP diesel engines, routinely handle 15 barges with a total capacity of 22,500 tons of cargo, the equivalent  of 225 freight cars or 1,125 18-wheelers.

In several places along the length of the Mississippi, the Corps of Engineers have built dams, blocking the water and raising it behind the dam to provide deeper access of shipping; at the same time, building locks alongside the dam so the ship could be raised from lower levels to higher levels in order to sail upriver

As for the changing conditions of the Mississippi, according to Frank Jacobs, “Shifting Like a Snake: Ancient Mississippi Courses,” the course of the Mississippi changes about every 1000 years, due to sediment buildup, which slows the river in places, typically in the southern portion, and forces it to find another route. The U.S. Corp of Engineers has concluded that we are about due for another 1000-year shift, with the Mississippi River flowing more fully into the Atchafalaya Basin River.
    Since no river on earth has been studied more than the Mississippi, it is probably the best understood river and history of any in the world. According to the Smithsonian, scientists have found that sedimentary rocks hold clues about the ancient environments in which they formed. Geologists who study the accumulation of sediments in the present observe that fine clays build up on the bottoms of ponds and other bodies of still water and on the floodplains of meandering rivers during periods of high water. Sandy sediments, on the other hand, build up in river channels and along river banks.
    Because the fossils found in the Washington, D.C. region are embedded in claystones and fine-grained sandstones, scientists conclude that a meandering river system flowed through this area in ancient times. The claystone and sandstone deposits we find today point to the positions of ponds, river channels and swamps in the ancient landscape.
    Again, according to the Smithsonian, careful attention paid to the precise locations of fossils in collection sites can give scientists additional clues about the physical structure of an ecosystem. The distribution of fossil deposits tell us that shrubs and ferns grew in open sites along river banks and around ponds, while conifer trees were dominant both in swampy forests and in drier upland forests set back from the river. In fact, scientists learned to interpret ancient landscapes by studying the ways that water and wind, carried sediments are deposited in modern landscapes, such as in meandering river systems.

Top: As the Mississippi River flows along it length, it separates and spreads, encompassing small branches, eddies, and sediment deposits along the way; Bottom: At the delta, it is swallowing up low-lying wetlands and turning them into open water

 

In addition, we know today that the Mississippi River delta is undergoing a catastrophic drowning, whereby 3100 square miles of low-lying wetlands have converted to open water over at least the past eight decades. Continued net land loss has been thought inevitable due to a decline in the load of total suspended sediment—both sand and mud—carried by the river. However, sand—which accounts for 50–70% of modern and ancient Mississippi delta deposits could be more important than mud for subaerial delta growth. Historically, half of the Mississippi River sediment load is supplied by the Missouri River and has not diminished in the lower 685 miles since dam construction, and based on numerical model of river morphodynamics predicts that the sand load feeding the delta will decrease only gradually over the next several centuries, with an estimated decline from current values of no more than about 17% within the coming six centuries.
    The drainage of the Missouri, upper Mississippi, Ohio, Arkansas, Tennessee rivers have all maintained the Lower Mississippi River relatively the same over the millennia because of the volume of water passing on through to the Gulf. A river by definition is only a quantity of water, flowing downhill, following a path of least resistance. The abundance of water that a river has to work with depends in large part upon a process called The Hydrological (Water) Cycle. It’s just a fancy name for the way that water first evaporates at lower elevations where it has collected – turns into rain, hail, or snow via condensation and transport – and then – the water precipitation falls over the higher elevations – again – causing it to flow back downhill across an irregular surface (above and below ground level), following gravity and a path of least resistance, to finally recollect again at the same lower elevations from which it came.

Geomorphotogy of the Old Mississippi River: Left: Over 1000 years ago; Middle: West Meander belt; Right: Shreve’s Cut

As an example, over a thousand years ago the Mississippi and Red were separate rivers and ran parallel, then in the 15^th century, the Westward meander belt of the Mississippi interceded with the Red and the Upper Red becoming a tributary to the Mississippi and the Lower Red becoming a distributary named the Atchafalaya River. Finally, in the 18^th century, Captain Henry M. Shreve cut off Turnbull’s bend by digging s canal

Three dams were built by the US Army Corps of Engineers in the floodgate system to keep the Mississippi River from changing course—view is to the east-southeast, looking downriver on the Mississippi, the Atchafalaya River is to the right; Bottom: two of the three dams shown in the middle of the image regulates water flow of 70% into the Mississippi and 30% into the Atchafalaya 

In 1963, the US. Army Corps of Engineers built a floodgate system of three dams across the Mississippi River to regulate the flow of water leaving the Mississippi into the Atchafalaya River and preventing the Mississippi from permanently changing course. Thus it cannot be said that “Nobody knows how the Mississippi river looked like 2000 years ago.” The Mississippi is the best understood river in the Western Hemisphere and its course has been plotted back thousands of years and is well mapped and documented.